• 한국통신학회논문지
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• 제33권12C호
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• pp.1062-1067
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• 2008

ABBA codes, a class of quasi-orthognal space-time block codes (QoSTBC) proposed by Tirkkonen and others, allow full rate and a fast maximum likelihood (ML) decoding, but do not have full diversity. In this paper, a linear complex precoder is proposed for ABBA codes to achieve full rate and full diversity. Moreover, the same diversity produce as that of orthogonal space-time block code with linear complex precoder (OSTBC-LCP) is achieved. Meanwhile, the size of the linear complex precoder can be reduced by half without affecting performance, which means the same complexity of decoding as that of the conventional ABBA code is guaranteed.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권3호
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• pp.101-105
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• 2004

The efficient power MOSFET inverter applied for a simple and low cost power supply is proposed for driving the dielectric barrier discharge (DBD) lamp load. For decades, the DBD phenomenon has been used for ozone gas production in industry. In this research, the ultraviolet and visible light sources utilizing the DBD lamp is considered as the load for solid-state high frequency power supply. It is found that the simple voltage-source single-ended quasi-resonant ZVS inverter with only one active power switch could effectively drive this load with the output power up to 700 W. The pulse density modulation based control scheme for the single-ended quasi-resonant ZVS inverter using a low voltage and high current power MOSFET switching device is proposed to provide a linear power regulation characteristic in the wide range 0-100％ of the full power as compared with the conventional control based Royer type parallel resonant inverter type power supplies.

• 조명전기설비학회논문지
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• 제27권2호
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• pp.84-94
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• 2013

In case when the existing TRIAC phase controlled dimmer is drove for the LED lighting equipments, there are many problems such as the LED flicker in low phase-angles, the acoustic noise and elements damage by increase of the peak voltage in the input filter capacitor, mulfunction by insufficiency of the TRIAC holding current, and the abnormal oscillation by LC resonant. In this paper, we proposes the single-stage quasi-resonant PSR(Primary Side Regulation) PWM converter, and the design, the simulation and experiment are performed. As a result, it could confirm that the proposed PWM converter is the lighting equipments for LED drive which can alternate the existing 60W class incandescent bulbs and it has the high drive performance of the efficiency 80% and over, the power factor 0.95 and over under the normal voltage 220V. Finally, total harmonic distortion(THD) is gratified with a standard[1] of the lighting equipments and the durability is evaluated as the high reliablilty of 150,000 hours and over.

• Journal of applied mathematics & informatics
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• 제31권3_4호
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• pp.337-342
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• 2013

In this paper, we study a special class of linear codes, called skew cyclic codes, over the ring $R=F_p+vF_p$, where $p$ is a prime number and $v^2=v$. We investigate the structural properties of skew polynomial ring $R[x,{\theta}]$ and the set $R[x,{\theta}]/(x^n-1)$. Our results show that these codes are equivalent to either cyclic codes or quasi-cyclic codes. Based on this fact, we give the enumeration of distinct skew cyclic codes over R.

• 디지털융복합연구
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• 제12권10호
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• pp.405-414
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• 2014

본 연구는 간호학생의 윤리적 의사결정 역량 강화 방안으로 2013년 3월 4일에서 6월 3일까지 간호대학 4학년 82명을 대상으로 실시한 비동등성 대조군 사전 사후 유사실험연구이다. 토론식 수업을 적용한 실험군과 전통적 강의식 수업을 적용한 대조군 간의 윤리 지식, 수업만족도 및 윤리적 가치관 차이를 확인하였다. 토론식 수업은 공리주의, 의무론에 기초한 3단계 수정모형과 Value-Be-Do 모형을 포함한 윤리적 의사결정 모형을 적용하였다. 연구결과 수업 후 윤리 지식 점수는 실험군이 유의하게 높았다. 윤리적 가치관은 두 군 모두 수업 전 후 차이가 없었다. 두 군은 수업 전 후 협동자관계 영역, 대상자관계 영역에서 의무론적 성향을 보였지만, 인간생명 영역에서 공리주의적 성향을 보였다. 수업만족도는 내용이해와 실무적용 가능성 영역에서 실험군이 유의하게 높았다. 결론적으로 본 윤리적 의사결정모형 기반 토론식 수업을 효과적인 간호윤리 의사결정 훈련 방안으로 활용할 것을 제안한다.

• International Journal of Contents
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• 제18권3호
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• pp.1-10
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• 2022

The advancement of Internet technologies has provided a new and effective way to cultivate international talents. To investigate the effect of native English teachers' online synchronous classes on Chinese primary school students' oral English improvement, an 18-month quasi-experimental study was conducted on 300 primary school students in China. The experiment and control groups were provided biweekly synchronous online classes with native and non-native English teachers. SPSS was used to conduct Paired Sample T-Tests and analyze performance differentials. The results showed that online classes taught by native English teachers perform better than non-native English teachers in three areas: vocabulary accuracy, average sentence length, and phonological intonation.

• 대한수학회지
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• 제56권4호
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• pp.1113-1129
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• 2019

We define a class of semi-symmetric metric connection on a Riemannian manifold for which the conformal, the projective, the concircular, the quasi conformal and the m-projective curvature tensors are invariant. We also study the properties of semisymmetric, Ricci semisymmetric and Eisenhart problems for solving second order parallel symmetric and skew-symmetric tensors on the Riemannian manifolds equipped with a semi-symmetric metric P-connection.

• Journal of Mechanical Science and Technology
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• 제15권9호
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• pp.1281-1291
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• 2001

The hereditary integral form of a quasi-linear viscoelastic law has been employed. Four new concepts have been employed: 1. a reduced relaxation function with a non-linear exponential function of time, 2. an inverse method to determine the scale factor of the elastic response, 3. an instant elastic recovery strain during unloading, and 4. the results of a constitutive model for cyclic tests may be a function of the Heavyside class. These concepts have been supported by agreement between measured and predicted responses of soft connective tissue to three types of multiple cyclic tests which include rest periods of no extension and alternations between different strain levels. Such agreement has not been attained in the previous studies. Chun and Hubbard (2001) is our companion experimental analysis paper.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.459-462
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• 2005

Recently, the PDP is the most remarkable media for a next generation display device. But the PDP is a high power consumption device. It is to required a high efficiency power supply. We reported the experimental result the high efficiency PDP power supply for 550w class. The proposed converter is quasi-resonant flyback topology, it achieves soft-switching in the single-switch flyback converter. As a result, we realize to very high efficiency power supply for PDP of 95% at 400v dc input and 550Watt output.

• 반도체디스플레이기술학회지
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• 제20권3호
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• pp.157-160
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• 2021

In this paper, a 20W class multi-output QR flyback converter for auxiliary power supply was designed to stabilize 4 output voltages, and the efficiency and load characteristics were compared and analyzed. It was checked if each output affects other output characteristics through experiment. As a result, the experimental circuit reached a high efficiency of 82.5% or more at a load power of over 20W, and the maximum power loss was 2.6W. Consequently, it was confirmed that all of 4 output voltages of the multi-output QR flyback converter constructed in this paper were stabilized within 0.5% in full-load range, and each output was independently controlled in an electrically isolated state.